A cleanroom is a controlled environment in which the concentration of airborne particles is controlled to specified limits. Airborne contamination must be continually removed from the air. The level to which these particles need to be removed depends upon the regulatory standards required. Whole room decontamination may be performed periodically or continuously to remove or neutralize contaminants from indoor environments to ensure that a desired decontamination level is achieved.
Clean room environments and whole room decontamination are of immense value in many industries, including healthcare, aerospace, medical device production, semiconductors, and pharmaceutical. The low density of environmental pollutants such as airborne microbes, bacteria, particles, and dust within these facilities reduces the amount of contamination within these facilities.
The only way to control contamination is to control the total environment. Eliminating airborne contamination is really a process of control. These contaminants are generated by people, process, facilities and equipment. For example, in the healthcare industry, it is estimated that between 5% and 10% of patients admitted to hospitals acquire one or more healthcare-associated infections, which leads to more than a million people worldwide being affected by infections acquired in hospitals. Health-care associated infections are also an important problem in extended care facilities, including nursing homes and rehabilitations units. These health-care acquired infections are associated with nearly 100,000 deaths annularly.
Patients infected with healthcare-associated microbes frequently contaminate items in their immediate vicinity with microbes that may remain viable on surfaces for days to weeks. Contaminated surfaces in healthcare facilities contribute to the spread of healthcare-associated microbes. In some instances, patients acquire microbes following direct contact with contaminated equipment or other surfaces. Contaminated surfaces can act as sources from which healthcare workers contaminate their hands. Healthcare workers can contaminate their hands by touching contaminated surfaces, and can transmit microbes if their hands are not cleansed appropriately.
Another critical source of contamination is inadequate cleaning of rooms after discharging a patient with certain contagious diseases, which puts subsequent patients admitted to the room at risk of acquiring the organism. Routine cleaning of patient rooms is often below the required standard. Therefore, improved cleaning and disinfection of the environment can reduce the risk of patients acquiring multi-drug resistant microbes. Cleaning, disinfecting and sterilization save lives and improve patient outcomes. Providing patients with a safe environment of care requires appropriate cleaning and disinfection of medical equipment and environmental surfaces.
Accordingly, much research has been devoted toward preventing growth of bacteria by the use of antimicrobial agents. Conventional techniques employed in the lighting industry to reduce bacterial growth and maintain a sanitary environment include, for example, using anatase type titanium dioxide (TiO2) or metal doped anatase type TiO2 like Zn, Si and Fe etc., as photocatalysts. This process exposes ultraviolet light to a catalyst such as titanium dioxide to produce primarily hydroxyl radicals (OH). These hydroxyl radicals are extremely reactive and can oxidize or “break down” pathogens and pollutants such that it can be used in indoor environments for air disinfection, as well as for contact-surface and materials disinfection. This process can be used to reduce indoor pathogens and pollutants to the extent that an acceptable indoor air quality can be achieved.
Therefore, antimicrobial agents comprising anatase TiO2 have been found to be useful blended with materials such as plastics, paintings and coatings, which also have applications in facilities such as hospitals. Oftentimes, these TiO2 antimicrobial agents have been applied as a coating within a lighting fixture installed in such facilities to disinfect the air and to clean surfaces contaminated with disease pathogens.
In addition, reflectors have also been an essential component of lighting applications for many years. In various types of reflectors, the reflective surfaces are coated with multilayer thin films. Such multilayer thin films typically incorporate a large number of thin layers of different light transmissive materials. The layers are often referred to as micro-layers, because they are thin enough so that the reflection and transmission characteristics of the film are determined in large part by constructive and destructive interference of light reflected from the layer interfaces.
Some reflective films are designed to reflect specularly. Such reflective surfaces can be formed from or coated with a highly specular material. Thus, the specular design of the highly specular surfaces can be a reflective base material or an applied highly specular coating.
The concept of specular reflection relates to the mirror-like reflection of light (or of other kinds of wave) from a surface, in which light from a single incoming direction (a ray) is reflected into a single outgoing direction. A pure specular reflector performs according to the law of reflection, which states “the angle of reflection equals the angle of incidence.”
One benefit of highly specular surfaces is the ability to maintain a uniform light intensity distribution, which is critically important in a LED lighting application.